On 22.08.23 15:56, Mark Brown wrote:
Use VM_HIGH_ARCH_5 for guarded control stack pages.
Signed-off-by: Mark Brown broonie@kernel.org
Documentation/filesystems/proc.rst | 2 +- fs/proc/task_mmu.c | 3 +++ include/linux/mm.h | 12 +++++++++++- 3 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 6ccb57089a06..086a0408a4d7 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -566,7 +566,7 @@ encoded manner. The codes are the following: mt arm64 MTE allocation tags are enabled um userfaultfd missing tracking uw userfaultfd wr-protect tracking
- ss shadow stack page
- ss shadow/guarded control stack page == =======================================
Note that there is no guarantee that every flag and associated mnemonic will diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index cfab855fe7e9..e8c50848bb16 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -711,6 +711,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ #ifdef CONFIG_X86_USER_SHADOW_STACK [ilog2(VM_SHADOW_STACK)] = "ss", +#endif +#ifdef CONFIG_ARM64_GCS
[ilog2(VM_SHADOW_STACK)] = "ss",
See my comment below.
}; size_t i; diff --git a/include/linux/mm.h b/include/linux/mm.h index 43fe625b85aa..3f939ae212e5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -372,7 +372,17 @@ extern unsigned int kobjsize(const void *objp);
- having a PAGE_SIZE guard gap.
*/ # define VM_SHADOW_STACK VM_HIGH_ARCH_5 -#else +#endif
+#if defined(CONFIG_ARM64_GCS) +/*
- arm64's Guarded Control Stack implements similar functionality and
- has similar constraints to shadow stacks.
- */
+# define VM_SHADOW_STACK VM_HIGH_ARCH_5 +#endif
Shouldn't that all just merged with the previous define(s)?
Also, I wonder if we now want to have CONFIG_HAVE_ARCH_SHADOW_STACK or similar.